Modern color negative films usually contain dyes coated in one or more layers for a variety of purposes. In addition to being utilized for spectral sensitization, dyes may be used for filtration of specific wavelengths of exposing light (either as intergrain absorbers or in separate layers containing no silver halide), for antihalation and for adjustment of the background density (Dmin) of color negative films for printing purposes. Dyes that are used to adjust Dmin for printing as well as for antihalation in color negative films are sometimes referred to as dummy dyes. Yellow and orange dyes that have been used in color negative films for antihalation and for Dmin adjustment have suffered from a number of deficiencies including poor dispersability, improper hue and instability on long term storage or on storage at elevated temperatures. Losses in blue density due to dye instability can result in improper color balance when prints are made from negatives that have been stored for appreciable times either before or after development.
Some yellow dummy dyes that are stable by themselves become unstable when coated in the same layer as other components, such as reducing agents that serve as scavengers for oxidized developer. Thus, there is a need for yellow dyes that retain stability in the presence of other chemicals typically incorporated into color negative films.
Orange dyes have been added to some color negative films, such as KODACOLOR GOLD films, to improve the color balance of color prints made on certain printers. Many color printers scan the average red, green and blue densities of a color negative and use these readings to automatically adjust exposures for proper density and color balance. The peak spectral sensitivities of printer scanners do not always match the peak sensitivities of a color paper. For example, the peak blue sensitivity of KODAK 3510 Printers occurs at approximately 440 nm, whereas the peak blue sensitivity of many color papers is at approximately 480 nm. When two color negative films that have different dye sets with different density ratios at 440 nm vs 480 nm are printed together using a printer such as the KODAK 3510 Printer, the resulting prints will have different color balances, and the two color negative films are said to be printer incompatible. An orange dye with additional absorption at 480 nm relative to 440 nm is sometimes added to the film with the lower absorption at 480 nm to render the two negative films more printer compatible. The orange dye C3 has been used for this purpose. However, this dye does not have good stability, and when negatives containing it are printed following long-term storage color imbalances may be observed. ##STR2##
One way to attack the instability problem associated with a dye such as C3 is to identify more stable orange dyes. Another approach is to identify stable yellow dyes or orange-yellow dyes with greater absorption in the region of 480 nm and to use such a dye to replace both the yellow and orange dummy dyes used conventionally in combination. It is further desired that such yellow or yellow-orange dummy dyes be readily dispersed and inexpensive to manufacture.
Japanese published patent application 63-064044 discloses photographic materials containing azoaniline dyes but the taught dyes have a maximum absorbance of 470 nm and thus do not have the structures that provide the appropriate dye hue for the purposes of our invention.
U.S. Pat. No.4,619,893 discloses azoaniline antihalation dyes but the patent does not specifically disclose photographic elements containing azoaniline dyes within the scope of our claims and having the structural features that provide the proper hue.
A problem to be solved is to provide photographic elements that contain dyes that produce prints of proper color balance and that provide a color balance that is not strongly altered during long-term storage due to the decomposition of the dyes.